Chronic total occlusion crossing devices and methods

ABSTRACT

A device for crossing a lesion in a tissue lumen includes a crossing wire configured to pass through a lumen of a catheter, the crossing wire including a loop at a distal end of the crossing wire. The loop can have a configuration that prevents a width of the loop from exceeding a width of the tissue lumen, and the loop having a pair of lateral opposing portions configured for alignment with a wall of the tissue lumen and a leading portion interconnecting the pair of lateral opposing portions, the leading portion being configured to interrogate the lesion. The loop has a length in an axial direction of the crossing wire extending from the leading portion to proximal ends of the pair of lateral opposing portions, the length being perpendicular to the width, and the length of the loop is at least twice the width of the loop.

This application is a continuation application of PCT/US2018/025722filed on Apr. 2, 2018, which claims priority to U.S. Non-Provisionalpatent application Ser. No. 15/666,279 filed Aug. 1, 2017, which claimspriority to U.S. Provisional Application No. 62/479,646 filed Mar. 31,2017 and U.S. Provisional Application No. 62/500,303 filed May 2, 2017,the entire contents of each of which are hereby incorporated byreference.

BACKGROUND 1. Technical Field

The field generally relates to crossing lesions in the vasculature,especially those referred to as a chronic total occlusions (CTO), and,more particularly crossing devices and methods utilizing a loop feature.

2. Discussion of Related Art

Vascular occlusions and, especially, CTOs can have a severe impact on apatient's health and lifestyle. CTOs are frequently encountered duringendovascular interventions. CTOs exist in many patients with symptomaticperipheral arterial disease. In the lower extremities, CTOs are commonlyencountered in the superficial femoral artery (SFA). Crossing theselesions may be challenging and may lead to prolonged procedure time,increased operator and patient radiation exposure, high contrast load,and peri-procedural complications including perforation, dissection,loss of collaterals, and creation of an arteriovenous fistula.

Revascularization of CTOs is usually hindered by failure to cross thelesion due to a variety of factors, so attempts to revascularize heavilycalcified CTOs still can meet with failure. Existing CTO crossingdevices still have a higher failure rate than desirable. Further,existing devices are too large to use in the vasculature below thewaist. There remains an unmet need for devices and methods that canreliably and effectively cross lesions.

There further remains a need for devices and methods that can be usedbelow the waist, including in the legs, such as the legs of diabeticpatients that experience particularly difficult blockages, includingperipheral artery disease (PAD). Such devices and methods would allowphysicians to reliably and effectively cross the CTO withoutconsequences such as perforating the vessel wall while attempting tocross the CTO. There remains an unmet need for effective and reliabletreatment options for crossing CTOs.

SUMMARY

A device for crossing a lesion in a tissue lumen includes a crossingwire configured to pass through a lumen of a catheter, the crossing wireincluding a loop at a distal end of the crossing wire, the loop having aconfiguration that prevents a width of the loop from exceeding a widthof the tissue lumen, and the loop having a pair of lateral opposingportions configured for alignment with a wall of the tissue lumen and aleading portion interconnecting the pair of lateral opposing portions,the leading portion being configured to interrogate the lesion. The loophas a length in an axial direction of the crossing wire extending fromthe leading portion to proximal ends of the pair of lateral opposingportions, the length being perpendicular to the width, and the length ofthe loop is at least twice the width of the loop.

According to one aspect, the loop has a rectangular cross-section,wherein the pair of lateral opposing portions are configured such that along edge of the rectangular cross-section contacts the wall of thetissue lumen for alignment with the wall of the tissue lumen.

According to one aspect, the loop has a rectangular cross-sectioncomprising two opposing long edges and two opposing short edges, whereinthe pair of lateral opposing portions and the leading portion of theloop form a plane, and wherein the two long edges are perpendicular tothe plane of the loop.

According to one aspect, a proximal end of the crossing wire has a firststiffness, and the leading portion of the loop has a second stiffness,wherein the first stiffness is greater than the second stiffness.

According to one aspect, the proximal end of the crossing wire forms aportion of a primary shaft of the crossing wire, wherein one of the pairof lateral opposing portions of the loop is directly connected to theprimary shaft, and wherein another of the pair of lateral opposingportions is directly connected to a secondary shaft of the crossingwire, the secondary shaft being configured to wrap around the primaryshaft.

According to one aspect, the crossing wire is twistable to form primaryand secondary shafts that are intertwined. According to one aspect, thecrossing wire has a rectangular cross-section, wherein the crossing wireforming the loop is not twisted, and wherein the crossing wire proximalto the loop is twisted.

According to one aspect, the crossing wire is configured to be rotatableback and forth through an angle less than 360 degrees while maintainingcontact with the lesion to erode the lesion.

According to one aspect, wherein the crossing wire is configured to betwisted through an angle greater than 360 such that lateral opposingportions of the crossing wire become entwined beyond the distal end ofthe catheter.

According to one aspect, the loop has a relaxed state such that oppositesides of the loop form an angle that is less than 90 degrees. Accordingto one aspect, the loop has a relaxed state such that opposite sides ofthe loop form an angle that is less than 60 degrees. According to oneaspect, the leading portion of the loop is flat. According to oneaspect, the leading portion of the loop is pointed. According to oneaspect, the crossing wire is integrally formed.

According to one aspect, the leading portion of the loop has a concaveconfiguration such that the pair of lateral opposing portions extenddistal to a center of the leading portion of the loop.

According to one aspect, the crossing wire has a variable stiffnessalong its length. According to one aspect, wherein the loop includes amaterial that is radiopaque.

A device for crossing a lesion in a tissue lumen includes a catheter; acrossing wire configured to pass through a lumen of the catheter, thecrossing wire including a loop at a distal end of the crossing wire, theloop having a configuration that prevents a width of the loop fromexceeding a width of the tissue lumen, and the loop having a pair oflateral opposing portions configured for alignment with a wall of thetissue lumen and a leading portion interconnecting the pair of lateralopposing portions, the leading portion being configured to interrogatethe lesion; and a stationary inner catheter disposed within thecatheter, the stationary inner catheter including a second lumentherein. An outer surface of the stationary inner catheter is fixed toan inner surface of the catheter.

According to one aspect, the device further includes a mobile innercatheter disposed within the lumen of the catheter eccentric to thestationary inner catheter, the mobile inner catheter forming a thirdlumen therein, the mobile inner catheter configured to move axially andradially with respect to the stationary inner catheter.

According to one aspect, a first proximal side of the loop is configuredto be disposed within the second lumen, and wherein a second proximalside of the loop is configured to be disposed within the third lumen.

A device for crossing a lesion in a tissue lumen includes a catheterforming a lumen; and a crossing wire configured to pass through thelumen of the catheter, the crossing wire including a primary shaft and aloop at a distal end of the primary shaft, the loop having aconfiguration that prevents a width of the loop from exceeding a widthof the tissue lumen, and the loop having a leading portion configured tointerrogate the lesion. The crossing wire has a first configuration inwhich opposing lateral sides of the loop are not twisted or are twistedby a first amount, and a second configuration wherein the opposinglateral sides of the loop are twisted by a second amount that isdifferent from the first amount. The crossing wire can be changed fromthe first configuration to the second configuration by twisting theprimary shaft at a position proximal to the catheter.

According to one aspect, a first side of the opposing lateral sides ofthe loop is directly connected to the primary shaft, a second side ofthe opposing lateral sides of the loop is directly connected to asecondary shaft of the crossing wire, and the primary shaft and thesecondary shaft are disposed inside the lumen of the catheter.

According to one aspect, in the second configuration, the opposinglateral sides of the crossing wire twist about each other a plurality oftimes. According to one aspect, a shape of the loop at a position distalto the catheter is configured to change when a rotational force isapplied to the primary shaft at a position proximal to the catheter.

A method for crossing a chronic total occlusion (CTO) includes insertinga catheter having a looped wire with a rectangular cross-sectiondisposed in a lumen of the catheter into an occluded vessel; extending adistal end of the looped wire beyond a distal end of the catheter tocontact an occlusion, the looped wire being positioned such that a longedge of the rectangular cross-section contacts a wall of the occludedvessel; grasping the looped wire at a position proximal to a proximalend of the catheter; and rotating the grasped looped wire back and forththrough an angle less than 360 degrees while maintaining the distal endof the looped wire in contact with the occlusion to erode the occlusion.

According to one aspect, the method further includes twisting thegrasped looped wire through an angle greater than 360 degrees whilepressing the distal end of the looped wire against the occlusion suchthat sides of the looped wire become entwined beyond the distal end ofthe catheter.

BRIEF DESCRIPTION OF THE DRAWINGS

Further objectives and advantages will become apparent from aconsideration of the description, drawings, and examples.

FIG. 1A shows a portion of a device for crossing a lesion according toone aspect of the invention.

FIG. 1B shows a crossing wire in a relaxed state.

FIG. 2 shows a device according to one aspect of the invention inside avessel lumen with a CTO.

FIG. 3A shows a first example of a looped wire.

FIG. 3B shows a second example of a looped wire.

FIG. 3C shows a third example of a looped wire.

FIG. 3D shows a fourth example of a looped wire.

FIG. 3E shows a fifth example of a looped wire.

FIG. 3F shows a fifth example of a looped wire.

FIG. 3G shows a fifth example of a looped wire.

FIG. 4 shows a device according to one aspect of the invention inside avessel lumen with a CTO where the device has begun to pass into the CTOlesion.

FIG. 5A shows a device according to one aspect of the invention wherethe loop is shown in a relaxed state.

FIG. 5B shows the device of FIG. 5A, but in another configuration.

FIG. 5C shows the device of FIG. 5A, but in another configuration in asequence of changing configurations from FIGS. 5A to 5B to 5C.

FIG. 5D shows the device of FIG. 5A, but in another configuration in asequence of changing configuration from FIGS. 5A to 5B to 5C to 5D.

FIG. 6A shows a device in one aspect of the invention positioned in thevasculature with a CTO, and the crossing wire is shown extended from thecatheter proximate the CTO cap.

FIG. 6B shows the device in FIG. 6A penetrating the CTO.

FIG. 6C shows the device of FIGS. 6A and 6B penetrating further into theCTO.

FIG. 6D shows the device of FIGS. 6A, 6B and 6C penetrating further intothe CTO and crossing the CTO.

FIG. 7A shows a crossing wire configured in one aspect of the invention.

FIG. 7B shows a crossing wire configured in another aspect of theinvention.

FIG. 7C shows a crossing wire configured in another aspect of theinvention.

FIG. 7D shows a crossing wire configured in another aspect of theinvention.

FIG. 8A shows a catheter with a side opening and a crossing wireconfigured in one aspect of the invention.

FIG. 8B shows a catheter with a side opening and a crossing wireconfigured in another aspect of the invention.

FIG. 8C shows a catheter with a side opening and a crossing wireconfigured in another aspect of the invention.

FIG. 8D shows a catheter with a side opening and a crossing wireconfigured in another aspect of the invention.

FIG. 8E shows a catheter and crossing wire with an inverted loopconfiguration according to some embodiments of the invention.

FIG. 9A shows a configuration of a looped crossing wire configured inone aspect of the invention.

FIG. 9B shows another configuration of a looped crossing wire configuredin one aspect of the invention.

FIG. 9C shows another configuration of a looped crossing wire configuredin one aspect of the invention.

FIG. 10 shows a device configured in one aspect of the invention, inwhich two additional inner catheters are disposed within the outercatheter.

FIG. 11A shows another configuration of a device with two additionalinner catheters disposed within the outer catheter.

FIG. 11B shows a configuration of a device with three additional innercatheters disposed within the outer catheter.

FIG. 11C shows an end of an outer catheter with three catheters disposedtherein.

FIG. 12 shows a configuration of a device wherein at least one innercatheter is mobile with respect to the outer catheter.

FIG. 13A shows a configuration of a device having a wheel to facilitatetwisting of the crossing wire.

FIG. 13B shows an enlarged image of the wheel of FIG. 13A.

FIG. 14 shows a configuration of a device in which a plurality ofcatheters are disposed within the outer catheter, and the outer catheterincludes a hole in a side surface.

FIG. 15A shows a configuration of a cross-section of a crossing wire.

FIG. 15B shows another configuration of a cross-section of a crossingwire.

FIG. 15C shows another configuration of a cross-section of a crossingwire.

FIG. 15D shows another configuration of a cross-section of a crossingwire.

FIG. 15E shows another configuration of a cross-section of a crossingwire.

FIG. 16 shows an example of a loop having a rectangular cross-section.

FIG. 17 shows arteries below the knee as an example vasculature in whichthe device can be used.

FIG. 18 shows a crossing wire in a twisted configuration.

FIG. 19A shows a crossing wire before it has been bent and cured orpreformed into a looped configuration.

FIG. 19B shows a crossing wire in another twisted configuration.

FIG. 20A shows a crossing wire in a loosely twisted configuration.

FIG. 20B shows a crossing wire in a moderately twisted configuration.

FIG. 20C shows a crossing wire in a stiff configuration.

FIG. 21A shows a crossing wire with a secondary shaft that is notconnected to the primary shaft at the proximal tip of the secondaryshaft.

FIG. 21B shows a crossing wire with a secondary shaft that is connectedto the primary shaft at the proximal tip of the secondary shaft.

FIG. 22 shows a configuration of a twisted wire forming a loop.

FIG. 23 shows another configuration of a twisted wire forming a loop.

FIG. 24 shows another configuration of a twisted wire forming a loop.

FIG. 25 shows another configuration of a twisted wire forming a loop.

FIG. 26 shows another configuration of a twisted wire forming a loop.

FIG. 27 shows another configuration of a twisted wire forming a loop.

FIG. 28A shows another configuration of a twisted wire forming a loop.

FIG. 28B shows another configuration of a twisted wire forming a loop.

FIG. 29 shows another configuration of a twisted wire forming a loop.

FIG. 30A shows a configuration of a crossing wire encased in an outershell.

FIG. 30B shows another configuration of a crossing wire encased in anouter shell.

FIG. 30C shows a configuration of a crossing wire that is not encased inan outer shell.

FIG. 31A shows a configuration of a crossing wire wherein the secondaryshaft has a length that can be varied.

FIG. 31B shows a configuration of a crossing wire wherein the secondaryshaft is not bonded to the primary shaft.

FIG. 31C shows a configuration of a crossing wire wherein the secondaryshaft is bonded to the primary shaft.

FIG. 32A shows a configuration of an outer shell of a crossing wire withan open distal end.

FIG. 32B shows a configuration of an outer shell of a crossing wire witha closed distal end.

FIG. 32C shows a configuration of a crossing wire extending beyond anopen distal end of an outer shell.

FIG. 33A shows a crossing wire having a first stiffness and an outershell.

FIG. 33B shows a crossing wire having a second stiffness and an outershell.

FIG. 33C shows a crossing wire having a third stiffness and an outershell.

FIG. 33D shows a crossing wire having a fourth stiffness and an outershell.

FIG. 34A shows a crossing wire having a circumferential configuration.

FIG. 34B shows a crossing wire having another circumferentialconfiguration.

FIG. 34C shows a crossing wire having another circumferentialconfiguration.

FIG. 35A shows a crossing wire having a circumferential configurationand two secondary shafts.

FIG. 35B shows a top-down view of the crossing wire shown in FIG. 35A.

FIG. 36 shows another configuration of a crossing wire having a primaryshaft and two secondary shafts.

FIG. 37A shows a configuration of a crossing wire having a primary shaftand a secondary shaft.

FIG. 37B shows an enlarged view of a portion of FIG. 37B.

FIG. 37C shows another configuration of a crossing wire having a primaryshaft and a secondary shaft.

FIG. 38A shows a crossing wires having a dual longitudinal helical wireconfiguration.

FIG. 38B shows a crossing wires having another dual longitudinal helicalwire configuration.

FIG. 39A shows a crossing wire having a circular cross-section at theloop.

FIG. 39B shows an enlarged image of the shaft in FIG. 39A.

FIG. 39C shows an enlarged image of the loop in FIG. 39A.

FIG. 39D shows a crossing wire having a rectangular cross-section at theloop.

FIG. 39E shows cross-section of a crossing wire having a rectangularcross-section at the loop.

FIG. 40 shows a configuration of a crossing wire that has a primaryshaft and a secondary shaft that are flat.

FIG. 41 shows another configuration of a crossing wire that has aprimary shaft and a secondary shaft that are flat.

FIG. 42 shows another configuration of a crossing wire that has aprimary shaft and a secondary shaft that are flat.

FIG. 43A shows a configuration of a crossing wire shaft.

FIG. 43B shows another configuration of a crossing wire shaft.

FIG. 43C shows another configuration of a crossing wire shaft.

FIG. 43D shows another configuration of a crossing wire shaft.

FIG. 44A shows a configuration of a crossing wire loop.

FIG. 44B shows another configuration of a crossing wire loop.

FIG. 45A shows another configuration of a crossing wire loop.

FIG. 45B shows another configuration of a crossing wire loop.

FIG. 46 shows a process for creating a wire having a non-circularcross-section in the loop portion from a wire having a circularcross-section.

FIG. 47A shows a configuration of a crossing wire having a non-circularcross-section.

FIG. 47B shows another configuration of a crossing wire having anon-circular cross-section.

FIG. 47C shows another configuration of a crossing wire having anon-circular cross-section.

FIG. 47D shows another configuration of a crossing wire having anon-circular cross-section.

FIG. 48A shows the crossing wire having a shaved cross-section at thedistal portion of the loop.

FIG. 48B shows a crossing wire having a shaved cross-section throughoutthe loop.

FIG. 48C shows a crossing wire having a loop that is not shaved.

FIG. 48D shows a distal end of a crossing wire that is formed from foursub-wires.

FIG. 49A shows a crossing wire in a loosely wound formation withabrasive elements on the loop.

FIG. 49B shows a crossing wire in a more tightly wound formation withabrasive elements on the loop.

FIG. 50A shows a configuration of a crossing wire having a welded loop.

FIG. 50B shows another configuration of a crossing wire having a weldedloop.

FIG. 51 shows a configuration of a crossing wire having a primary shaftand a secondary shaft.

DETAILED DESCRIPTION

Some embodiments of the current invention are discussed in detail below.In describing embodiments, specific terminology is employed for the sakeof clarity. However, the invention is not intended to be limited to thespecific terminology so selected. A person skilled in the relevant artwill recognize that other equivalent components can be employed andother methods developed without departing from the broad concepts of thecurrent invention. All references cited anywhere in this specification,including the Background and Detailed Description sections, areincorporated by reference as if each had been individually incorporated.

The devices and methods contemplated are configured to reliably andeffectively cross lesions in the vasculature, especially, lesions of thetype where the accumulation of plaque is so severe that it results in acomplete or nearly complete blockage of the vessel. The devices andmethods in accordance with the principles of the invention areconfigured and adapted to cross an occlusion in order thatinterventional treatments can follow. The devices and methods describedcan include a crossing wire, a crossing catheter, and/or a combinationof both utilized separately and/or in combination with each other and/orin combination with conventional wires and/or catheters.

The CTO crossing devices and methods can include a guidewire having adistal end configured for more reliably crossing a CTO. In one aspectthis configured distal end can be referred to as a loop, as discussed inmore detail below. This loop-ended crossing wire is configured topresent a more reliable device for interaction and engagement with theCTO, and, more particularly, a cap of the CTO that can have varyinggeometries and complexities. The loop-ended crossing wire is alsoconfigured to present a more reliable device for advancing through theocclusion to successfully cross the lesion.

The configuration at the end of the guide wire, referred to as a loop,can include various geometries, shapes, sizes and material propertiesand can be configured by way of the contemplated methods alone and/or incombination with guidewires and/or catheters. The loop feature, and theassociated methods and/or devices, can be configured to present aninterrogation conducive distal leading end that balances loop resiliencywith stiffness so as to present itself optimally to the lesion yet alsoallow the loop to pass through the lesion. The loop configuration can beachieved by shape-memory and/or arrangements of the wire alone, incombination with a catheter, and/or in combination with methods of use.For example, the guidewire loop can include a loop shape prior to useand/or a loop configuration that is formed in whole or in part in-situ,alone and/or in combination with a catheter.

A device for crossing a lesion in a tissue lumen includes a crossingwire configured to pass through a lumen of a catheter, the crossing wireincluding a loop at a distal end of the crossing wire, the loop having aconfiguration that prevents a width of the loop from exceeding a widthof the tissue lumen, and the loop having a leading portion configured tointerrogate the lesion.

According to one aspect, the device further includes the catheter,wherein the catheter has a proximal end and a distal end. According toone aspect, a first proximal side of the loop is configured to bedisposed within the lumen of the catheter, and a second proximal side ofthe loop is configured to be disposed outside of the lumen of thecatheter. According to one aspect, a first proximal side of the loop anda second proximal side of the loop are configured to be disposed withinthe lumen of the catheter.

According to one aspect, the catheter further includes a hole in a sidesurface of the catheter, wherein a first proximal side of the loop isconfigured to be disposed within the lumen of the catheter, and whereina second proximal side of the loop is configured to enter the lumen ofthe catheter through the hole in the side surface of the catheter.

According to one aspect, the crossing wire is twistable to form a loophaving opposite sides that are intertwined. According to one aspect, theloop has a relaxed state such that opposite sides of the loop form anangle that is less than 90 degrees. According to one aspect, the loophas a relaxed state such that opposite sides of the loop form an anglethat is less than 60 degrees.

According to one aspect, the leading portion of the loop is rounded.According to one aspect, the leading portion of the loop is flat.According to one aspect, the leading portion of the loop is pointed.

According to one aspect, the crossing wire is integrally formed.According to one aspect, the crossing wire has a single stiffness alongits length. According to one aspect, the crossing wire has a variablestiffness along its length. According to one aspect, the crossing wirehas a cross-section that is rectangular.

According to one aspect, the device further includes a stationary innercatheter disposed within the catheter, the stationary inner catheterincluding a second lumen therein. An outer surface of the stationaryinner catheter is fixed to an inner surface of the catheter. Accordingto one aspect, the device further includes a mobile inner catheterdisposed within the lumen of the catheter eccentric to the stationaryinner catheter, the mobile inner catheter forming a third lumen therein,the mobile inner catheter configured to move axially and radially withrespect to the stationary inner catheter. According to one aspect, afirst proximal side of the loop is configured to be disposed within thesecond lumen, and a second proximal side of the loop is configured to bedisposed within the third lumen.

According to one aspect, the crossing wire is an elongated wire. Thecrossing wire has a proximal end controllable by a user, wherein thedistal end of the crossing wire is configured for positioning in thetissue lumen for crossing a chronic total occlusion, the distal endincluding the loop, the loop having a pair of lateral opposing portionsconfigured for alignment with a wall of the tissue lumen and the leadingportion interconnecting the pair of lateral opposing portions, whereinthe loop is configured for crossing the chronic total occlusion.

According to one aspect, the proximal end of the crossing wire has afirst stiffness, and wherein the leading portion of the loop has asecond stiffness, wherein the first stiffness is greater than the secondstiffness. According to one aspect, the loop includes a material that isradiopaque. According to one aspect, the proximal end of the crossingwire forms a portion of a primary shaft of the crossing wire, whereinone of the pair of lateral opposing portions of the loop is directlyconnected to the primary shaft, and wherein another of the pair oflateral opposing portions is directly connected to a secondary shaft ofthe crossing wire, the secondary shaft being configured to wrap aroundthe primary shaft.

According to one aspect, the crossing wire is configured to be rotatableback and forth through an angle less than 360 degrees while maintainingcontact with the lesion to erode the lesion. According to one aspect,the crossing wire is configured to be twisted through an angle greaterthan 360 such that lateral opposing portions of the crossing wire becomeentwined beyond the distal end of the catheter.

A method for crossing a chronic total occlusion (CTO) includes insertinga catheter having a looped wire disposed in a lumen of the catheter intoan occluded vessel; extending a distal end of the looped wire beyond adistal end of the catheter to contact an occlusion; grasping the loopedwire at a position proximal to a proximal end of the catheter; androtating the grasped looped wire back and forth through an angle lessthan 360 degrees while maintaining the distal end of the looped wire incontact with the occlusion to erode the occlusion.

According to one aspect, the method further includes twisting thegrasped looped wire through an angle greater than 360 degrees whilepressing the distal end of the looped wire against the occlusion suchthat sides of the looped wire become entwined beyond the distal end ofthe catheter.

A device for crossing a lesion in a tissue lumen includes a catheterforming a lumen; and a crossing wire configured to pass through thelumen of the catheter, the crossing wire including a primary shaft and aloop at a distal end of the primary shaft, the loop having aconfiguration that prevents a width of the loop from exceeding a widthof the tissue lumen, and the loop having a leading portion configured tointerrogate the lesion. The crossing wire has a first configuration inwhich opposing lateral sides of the loop are not twisted or are twistedby a first amount, and a second configuration wherein the opposinglateral sides of the loop are twisted by a second amount that isdifferent from the first amount. The crossing wire can be changed fromthe first configuration to the second configuration by twisting theprimary shaft at a position proximal to the catheter.

According to one aspect, a first side of the opposing lateral sides ofthe loop is directly connected to the primary shaft, a second side ofthe opposing lateral sides of the loop is directly connected to asecondary shaft of the crossing wire, and the primary shaft and thesecondary shaft are disposed inside the lumen of the catheter. Accordingto one aspect, in the second configuration, the opposing lateral sidesof the crossing wire twist about each other a plurality of times.According to one aspect, a shape of the loop at a position distal to thecatheter is configured to change when a rotational force is applied tothe primary shaft at a position proximal to the catheter.

A device for crossing a lesion includes a catheter including a lumen,the catheter having a proximal end and a distal end, and a crossing wireconfigured to pass through lumen, the crossing wire including a loop ata distal end of the crossing wire, the loop having a relaxed state suchthat opposite sides of the loop form an angle that is less than 180degrees, and the loop having a leading portion configured to interrogatethe lesion.

According to one aspect, a first proximal side of the loop is configuredto be disposed within lumen of the catheter, and a second proximal sideof the loop is configured to be disposed outside of the lumen of thecatheter. According to one aspect, a first proximal side of the loop anda second proximal side of the loop are configured to be disposed withinlumen of the catheter. According to one aspect, the catheter furtherincludes a hole in a side surface of the catheter, wherein a firstproximal side of the loop is configured to be disposed within the lumenof the catheter, and wherein a second proximal side of the loop isconfigured to enter the lumen of the catheter through the hole in theside surface of the catheter.

According to one aspect, the crossing wire is twistable to form a loophaving opposite sides that are intertwined. According to one aspect, theloop has a relaxed state such that opposite sides of the loop form anangle that is less than 90 degrees. According to one aspect, a firstproximal side and a second proximal side of the loop are configured tobe disposed within lumen of the catheter. According to one aspect, theloop has a relaxed state such that opposite sides of the loop form anangle that is less than 60 degrees. According to one aspect, the leadingportion of the loop is rounded. According to one aspect, the leadingportion of the loop is flat. According to one aspect, the leadingportion of the loop is pointed.

According to one aspect, the crossing wire is integrally formed.According to one aspect, the crossing wire has a single stiffness alongits length. According to one aspect, the crossing wire has a variablestiffness along its length. According to one aspect, the wire has across-section that is rectangular.

According to one aspect, the device further includes a stationary innercatheter disposed within the support catheter, the stationary innercatheter including a second lumen therein. An outer surface of thestationary inner catheter is fixed to an inner surface of the supportcatheter.

According to one aspect, the device further includes a mobile innercatheter disposed within the lumen of the support catheter eccentric tothe stationary inner catheter, the mobile inner catheter forming a thirdlumen therein, the mobile inner catheter configured to move axially andradially with respect to the stationary inner catheter.

According to one aspect, a first proximal side of the loop is configuredto be disposed within the second lumen, and a second proximal side ofthe loop is configured to be disposed within the third lumen.

A device for crossing a lesion includes a catheter including a lumen,the catheter having a proximal end and a distal end, and a crossing wireconfigured to pass through lumen, the crossing wire including a loop ata distal end of the crossing wire, the loop having opposite sides thatare disposed within the lumen, and the loop having a leading portionconfigured to interrogate the lesion.

A chronic total occlusion crossing wire includes an elongated wireconfigured to pass through a catheter lumen, the elongated wire having aproximal end controllable by a user and a distal end configured forpositioning in a vessel for crossing the chronic total occlusion, thedistal end including a loop having a pair of lateral opposing portionsconfigured for alignment with a wall of the vessel and a leading portioninterconnecting the pair of lateral opposing portions, wherein the loopis configured for crossing the chronic total occlusion.

According to one aspect, the proximal end of the elongated wire has afirst stiffness, and the leading portion of the loop has a secondstiffness, wherein the first stiffness is greater than the secondstiffness. According to one aspect, the loop includes a material that isradiopaque. According to one aspect, the proximal end of the elongatedwire forms a portion of a primary shaft of the elongated wire, whereinone of the lateral opposing portions of the loop is directly connectedto the primary shaft, and wherein another of the lateral opposingportions is directly connected to secondary shaft of the elongated wire,the secondary shaft being configured to wrap around the primary shaft.

A method for crossing a chronic total occlusion (CTO) includes insertinga catheter having a looped wire disposed in a lumen of the catheter intoan occluded vessel, and extending a distal end of the looped wire beyonda distal end of the catheter to contact an occlusion. The method furtherincludes grasping the looped wire at a position proximal to a proximalend of the catheter, and rotating the grasped looped wire back and forththrough an angle less than 360 degrees while maintaining the distal endof the looped wire in contact with the occlusion to erode the occlusion.

In one aspect, the method further includes twisting the grasped loopedwire through an angle greater than 360 degrees while pressing the distalend of the wire against the occlusion such that sides of the looped wirebecome entwined beyond the distal end of the catheter.

A CTO crossing device according to some embodiments of the invention isdirected to the concept of a loop at the distal end of the system, inparticular, a guidewire loop. With this loop, the physician has theability to use the leading distal end of the loop to interrogate thelesion and ultimately cross the lesion. The term “interrogate” as usedherein can mean to contact, prod, probe, chip away at, break apart,dissect, and/or drill into a lesion. While interrogating a lesion maylead to crossing the lesion, the term “interrogating” is generally usedto mean physically interacting with the lesion. The loop at the distalend of the system provides a stiffer surface for interrogating thelesion compared to, for example, using the floppy distal wire tip of aconventional guidewire.

Various aspects of the loop configuration can be considered. One aspectof the configuration is a dimensional configuration, such as the widthof the loop. The width of the loop can be generally considered a lateraldimension. The width dimension of the loop can be configured based onthe width or transverse dimension of the vessel in which the lesion islocated. For example, the width may be configured to be half of thecross-sectional diameter of the vessel.

The loop can be configured to maintain geometries and/or configurationsin use that allow crossing of the lesion without the loop collapsingand/or puncturing unintended areas of the vasculature. If the width ofthe loop exceeds the width of the vessel, or if the loop collapses, thevessel can rupture. The loop width can be selected to allow the loop tomove along the vessel wall gently, without exerting point-like pressureon the vessel wall, and/or without exerting forces perpendicular to thevessel wall. According to one aspect, the width of the loop is betweenabout 0.05 mm and about 6 mm According to one aspect, the width of theloop is between about 1.5 mm and about 2.5 mm According to one aspect,the width of the loop is between about 2.5 mm and about 6 mm.

In one aspect, the device can be configured to limit the width of theloop to be about half the width of the vessel. For example, for a 5 or 6mm vessel, the width of the loop will less than about 2.5 or 3 mm Anarrow loop can move along the vessel wall without exerting point-likepressure on the vessel wall, and without exerting forces perpendicularto the vessel wall. If the width of the loop were allowed to expand suchthat it significantly exceeded the diameter of the vessel, the sides ofthe loop may exert forces perpendicular to the surface of the vesselwall that could puncture the vessel wall.

The loop can have a configuration that prevents a width of the loop fromexceeding a width of the tissue lumen. The configuration may prevent thewidth of the loop from exceeding the width of the tissue lumen to thepoint of rupture, risk of rupture, undesirable stress and/or strain onthe vessel, or beyond the vessel's elastic limits. In one aspect, theloop configuration may prevent the width of the loop from exceeding awidth that is slightly greater than the diameter of the tissue lumenwhen no forces are being applied, because the shape of the lumen maychange when an expanding force is applied by the loop, increasing thewidth of the lumen. In one aspect, the configuration may prevent thewidth of the loop from exceeding the width of the tissue lumen to thepoint of injury. In one aspect, the configuration may provide a loopthat is not damaging to the healthy lumen size and/or shape of thelumen. In one aspect, the configuration controls the width of the loopto be about half the diameter of the tissue lumen or less. In oneaspect, the configuration controls the width of the loop relative to thelumen diameter. In one aspect, the configuration controls the width ofthe loop relative to the lesion.

The distal-most portion of the loop is referred to herein as the leadingdistal end, or leading portion. The leading distal end of the loop canbe configured in accordance with the principles of the invention to havea size and shape that are optimized for a particular application. Forexample, the leading distal end can be pointed, rounded, convex, orconcave depending on the shape and hardness of the lesion to beinterrogated.

The leading distal end of the loop can be configured to come intocontact with the lesion. The distal end of the loop can be generallyconfigured with a curvature of various types, some of which are shown inthe drawings and discussed below. In one aspect, the leading distal endcan be configured to be pointed, providing a smaller surface area forcontacting the occlusion as compared to a loop having a rounded leadingend. When the leading distal end contacts the lesion, the pointedleading distal end concentrates a force applied to the lesion over asmaller area of the lesion than a rounded leading distal end would.

The loop portion of the crossing wire can be pre-formed such that theleading distal end of the loop has a predetermined configuration. Forexample, the crossing wire can assume a looped or bent shape even whenno external forces are acting on it. When no forces are acting on theloop, the configuration of the loop can be referred to as a “relaxed” orsteady-state configuration. The fact that the loop is pre-formed helpsmaintain the narrow width of the loop, because the crossing wire itselfwill provide a counter-force when the loop is expanded beyond itspre-formed width. For example, when the leading distal end of the loopis brought into contact with a lesion and additional force is applied tothe crossing wire, if the lesion resists the applied forces, the loopmay begin to expand. However, the crossing wire itself will providetensile forces that resist expansion of the loop beyond its preformedwidth. The widest portions of the loop can contact the vessel wall, andcan stabilize the loop with respect to the vessel wall, such as thearterial wall.

In addition to the loop configuration contemplated in its basic form asdiscussed above in various aspects and configurations, the loop canfurther be configured to include more complex loop configurations. Theadditional loop configurations can have a single loop configuration asthe basis of the loop configurations. The loop can be configured toallow for twisting and/or wrapping of the loop during use.

The loop alone and/or in combination with the catheter can be configuredto be adaptable and/or controlled during use by methods and techniquescontemplated herein. In one aspect, during use of the CTO crossingdevice, the operator, such as a physician, can control the crossing wireby displacement, for example, such as by rotation and/or twisting. Theoperator can twist a portion of the wire proximal to the catheter,causing a portion of the wire extending beyond the distal end of thecatheter to become intertwined with itself. This can prevent the loopfrom becoming too wide, and also provides axial support for the leadingportion of the loop.

The present device enables the physician to control the width of theloop, thereby enhancing the safety and efficacy of the procedure. Someconfigurations of the invention also include a catheter, into which thelooped crossing wire is disposed. By disposing the wire inside thecatheter, the amount of bowing that the wire can undergo is limited. Ifthe wire begins to bow inside the catheter, the catheter wall redirectsthe lateral forces so that they extend along the length of the catheter,and toward the leading distal end of the loop.

A device for crossing a lesion according to some embodiments of theinvention is shown in FIG. 1A. The device 100 includes a catheter 102including a lumen 104, the catheter 102 having a proximal end 106 and adistal end 108. The device also includes a crossing wire 110 configuredto pass through lumen 104, the crossing wire 110 including a loop 112 ata distal end of the crossing wire 110, the loop 112 having a relaxedstate such that opposite sides 114, 116 of the loop form an angle thatis less than 180 degrees, and the loop 112 having a leading portion 118configured to interrogate the lesion.

The term “relaxed state” is intended to mean a state of the crossingwire when no external forces are exerted on it. For example, FIG. 1Bshows a crossing wire 120 in a relaxed state. The opposite sides 122,124 of the loop 126 can form an angle 128. The angle can be less than180 degrees. In one aspect of the invention, the angle is between about90 and about 45 degrees. In one aspect of the invention, the angle isbetween about 60 and about 30 degrees. The angle will influence thewidth of the looped portion of the crossing wire. A crossing wire withopposite sides that form an angle of 90 degrees in a relaxed state willform a wider loop than a crossing wire with opposite sides that form anangle of 45 degrees in a relaxed state. The angle may be chosen based onthe diameter of the vessel, with smaller angles corresponding to smallervessels and larger angles corresponding to larger vessels. Further,loops forming a wider angle may be chosen for navigating the true lumenof a vessel during a CTO crossing procedure, while loops forming anarrower angle may be chosen for navigating the subintimal region of thevessel, if the CTO cannot be crossed with the loop remaining in the truelumen.

FIG. 2 shows a catheter 200 inside a vessel lumen 202. A CTO 204 blocksthe lumen 202. A CTO wire 206 is shown extending beyond the distal endof the catheter 200. The CTO wire 206 has a loop 208 that forms thedistal end of the CTO wire 208. The loop 208 can come into contact withthe CTO 204, and can be used by the physician to perform microdissectionof the CTO, opening the vessel and creating a path for a guide wire orother device if further treatment is required. The physician my usemultiple looped CTO wires to cross the CTO. For example, the physicianmay use a first looped CTO wire from an antegrade approach and a secondlooped CTO wire from a retrograde approach.

The CTO wire can undergo structural formation such that, when no forcesare applied to the wire, the wire assumes the configuration or shape asshown, where a portion of the wire doubles back. For example, in FIG. 2,the CTO wire 206 has a main shaft 210, a loop 212, and a second shaft212 that doubles back toward the catheter 200. The wire including thedouble-backed portion may form a V-shape, a U-shape, a W-shape, or anM-shape, for example. These shapes are provided as examples, and theembodiments of the invention are not limited to these shapes. The wireincluding the doubled-back portion may be referred to herein as“looped.” Loop 208 can be pre-formed, and can have shape memorycharacteristics. The shape memory characteristics allow the loop toresist forces that would cause the loop to become wider. For example, ifthe loop 208 is pre-formed to have a particular width, when a force isexerted on the loop that would cause the width of the loop to increase,tensile forces in the wire will resist the lateral forces, helpingmaintain the predetermined width of the loop. The loop 208 can bepassable through the catheter and can assume its relaxed configurationin whole or in part for use.

The structural formation of the wire can be accomplished by a variety ofmethod, for example, by forming the wire to have a looped shape duringits original manufacture, or by applying heat and shaping forces to thewire after its initial formation. Once the wire has undergone structuralformation, the wire maintains its structural formation when it is in arelaxed configuration, meaning that no forces are applied to it. Whenforces are applied to the wire that would change the configuration ofthe wire, the tensile forces in the wire resist the change. However, thewire may still flex and bend due to the applied forces.

FIGS. 3A-3G show various configuration of looped wires. Eachconfiguration may be a result of the structural formation of the wire,and may be the relaxed configuration of the wire. In FIG. 3A, the wire300 has a broad loop. In FIG. 3B, the wire 302 has a broad loop with aflattened tip. In FIG. 3C, the wire 304 has a broad loop with a pointedtip. In FIG. 3D, the wire 306 has an elongated loop with a narrow tip.In FIG. 3E, the wire 308 has a broad loop with one end of the wirelocated very close to the loop. In FIG. 3F, the wire 310 has a peakedloop. This loop may be used to interrogate a concave lesion. In FIG. 3G,the wire 312 has an inverted loop 314. The leading portion of theinverted loop 314 has a concave configuration such that the pair oflateral opposing portions 316, 318 extend distal to the center 320 ofthe leading portion of the loop 314. As shown in FIG. 3G, the loop 314may form a “W” shape, with the pair of lateral opposing portions 316,318 extending the farthest distally, then the loop extending proximallya first distance, and then again distally a second distance to thecenter 320 of the leading portion of the loop 314. The second distancemay be less than the first distance, as shown in FIG. 3G. The loop 314may be used to interrogate a convex lesion. The pair of lateral opposingportions 316, 318 can engage the sides of the lesion and the walls ofthe tissue cavity, thus centering the loop on the lesion. The center 320of the leading portion of the loop 314 can interrogate the lesion as thephysician pushes the wire 312 distally and rotates the wire 312. Thus, aphysician may select a particular wire based on the shape and density ofthe lesion.

According to one aspect of the invention, the crossing wire has a shortside on one side of the loop, and a long side on the other side of theloop. The long side of the loop can be disposed within a catheter, whilethe short side may be disposed within the catheter, or outside of thecatheter. According to one aspect of the invention, the short side has alength between about 10 mm and about 70 mm According to one aspect ofthe invention, the short side has a length between about 30 mm and about50 mm According to one aspect of the invention, the short side has alength of about 40 mm According to one aspect of the invention, bothsides of the loop are the same length.

FIG. 4 shows how the looped wire can be used to cross a lesion accordingto one aspect of the invention. A physician guides the catheter 400through the vessel until it is within a few millimeters of the lesion402. The catheter 400 has a crossing wire 404 that is at least partiallydisposed inside the catheter or passed through the catheter. Thecrossing wire 404 has a length such that it can be grasped by thephysician proximal to the catheter 400, and can simultaneously extendbeyond the distal end of the catheter 400. Once the catheter 400 is inposition, the physician then extends the crossing wire 404 beyond thedistal end of the catheter 400, toward the lesion 402. The looped wirein FIG. 4 can be representative of any of the configurations andembodiments of looped wires described herein.

The crossing wire 404 has a pre-formed loop. For example, the pre-formedloop may have a relaxed configuration with a primary shaft, a secondaryshaft, and a loop portion between the primary and secondary shafts. Theprimary and second shafts may be separated by a space, as shown in FIGS.3A-3G. The physician extends the crossing wire 404 until the leadingdistal end 406 contacts the lesion 402. Once the leading distal end 406contacts the lesion 402, the physician may probe the lesion with theleading distal end 406. Further, the physician may grasp the crossingwire 404 proximal to the catheter 400, and begin to twist the wire. Thetwo sides of the pre-formed loop begin to twist around themselves,forming a twisted loop 408, as shown in FIG. 4. The twisted loop 408 canhave a higher resistance to bending than a conventional CTO wire,allowing the physician to exert greater force on the lesion 402 thanwould be possible with a conventional CTO wire, while maintain a loopwhose width does not exceed the width of the vessel. The physician maycontinue twisting the wire as he or she applies pressure on the lesion402, thereby entering into the lesion 402, as shown in FIG. 4. Thedevice entering into the lesion can be referring to as drilling into thelesion. In this way, the physician may use the wire to performrepetitive microdissection of the lesion 402, creating a clear path.

FIGS. 5A-5D show a crossing wire in various configurations. Each of theconfigurations shown in FIGS. 5A-5D may be used to interrogate and/orcross a lesion. A particular configuration may be chosen based on avariety of considerations, including the size, shape, and hardness ofthe lesion, for example. The wire may be preformed to have a loop, as inFIG. 5A, that can be twisted to obtain the configurations in FIGS.5B-5D. Alternatively, the wire may be preformed to have a twistedconfiguration, such as the configurations shown in FIGS. 5B-5D.

In FIG. 5A, the crossing wire 500 has two ends that are side-by-side.This can be the state of the crossing wire before the physician beginsto apply a torque, or twisting motion, to the wire. The crossing wire500 can be used to advance the wire through a vessel or for pedal loopcrossing. In FIG. 5B, the crossing wire 502 has been twisted slightlysuch that the two sides of the wire have become intertwined. In FIG. 5C,the crossing wire 504 has undergone additional twisting, causing the twosides of the crossing wire to become more tightly intertwined, andcausing the loop to become narrower. Intertwining the two sides of thewire increases the stiffness of the wire, providing additional columnstrength for applying a force on the lesion. The crossing wire 506 inFIG. 5D has undergone even more twisting, causing the two sides of thewire to become even more tightly intertwined, and the loop at the end ofthe wire to become even narrower. Of the wires 500-506 shown in FIGS.5A-5D, the tightly intertwined wire 506 will be most resistant tobending, and therefor can be used to apply a strong force to the lesion.Softer lesions may not require such a strong force, and one of the otherthree wires 500-504 may be sufficient to cross the lesion. The number ofrotations and amount of turns or twists in the loop is variable and canbe dependent upon the lesion type/hardness. The operator can control thenumber of twists. The device can be configured to enable the quantity oftwists that the crossing wire is capable of forming.

FIGS. 6A-6D show a device in one aspect of the invention positioned inthe vasculature with a CTO. The physician begins by obtaining arterialor venous access, and then placing a sheath in the artery or vein. Thephysician may image the region of interest, for example, using anangiogram, to determine the position of the CTO. As shown in FIG. 6A,the physician may then guide the catheter 600 into close proximity ofthe lesion 602. The physician then extends the crossing wire 604 beyondthe distal end of the catheter 600 until a leading portion 606 of theloop 608 at the distal end of the crossing wire 604 engages the lesion602.

According to one aspect of the invention, the crossing wire 604 has mainshaft 610 on one side of the loop 608 and a secondary shaft 612 on theother side of the loop 608. One or both of the main shaft 610 and thesecondary shaft 612 extend back into the catheter 600. At least one ofthe shafts extends the length of the catheter so that it can bemanipulated by the physician. Herein, the shaft that is manipulated isreferred to as the “main shaft,” though in some configurations of thedevice the physician may manipulate both shafts. In FIGS. 6A-6D, themain shaft 610 extends through the catheter 600, while the secondaryshaft 612, is shorter, and may not be disposed within the catheter 600while the physician performs the procedure.

Once the leading portion 606 of the crossing wire 604 contacts thelesion 602, the physician begins twisting the main shaft 610 of thecrossing wire 604, as shown in FIG. 6B. The secondary shaft 612 becomesintertwined with the main shaft 610, providing column strength to thecrossing wire 604, and causing the loop 608 to become narrower. Thephysician continues twisting the main shaft 610 and applying pressureuntil the loop 608 crosses the lesion 602, as shown in FIGS. 6C and 6D.

While the physician is applying pressure to main shaft 610, the lesion602 may resist the force of the distal portion 606 of the loop 608. Theaxial forces applied by the physician may then be redirected laterally,causing the loop 608 to flex. However, because the loop 608 is formed tohave a predetermined width in its relaxed configuration, the loop 608will resist axial forces that would cause it to become wider than thewidth of the vessel. Further, by twisting the main shaft 610 and therebyintertwining the main shaft 610 with the secondary shaft 612, thephysician maintains the width of the loop to be narrower than the widthof the vessel.

The physician may twist the main shaft 610 in a single direction, or mayrotate the wire back and forth to erode the lesion 602. According to oneaspect of the invention, the physician twists the main shaft 610 untilthe crossing wire 604 has about three or four nodes, or crossing points,in the loop 608. Additional nodes may decrease the resistance of thewire to lateral forces. If the nodes do not remain in a straight linewhen lateral forces are applied, the loop 608 may collapse, and the wallof the vessel could rupture.

FIGS. 20A-20C show wires in three twisted configurations. In FIG. 20A,the secondary shaft 2000 is loosely twisted around the primary shaft2002. The primary shaft 2000 can be alternately twisted clockwise andcounter-clockwise to maintain the loosely twisted configuration as thedistal tip 2004 contacts and crosses the CTO. The left and rightrotations can be a point of variation between 0° and 360°. If theprimary shaft 2002 is initially twisted in a clockwise direction toobtain the loosely twisted configuration, additional clockwise rotationwill tighten the wire and increase the crossing force applied by thedistal tip 2004 of the CTO crossing wire on a lesion.

The 0°-360° rotation can be used as a back and forth motion or acontinuous clockwise (or counter-clockwise) rotation. The rotation ofthe wire is at the discretion of the user and may depend on the forcerequired to cross the CTO. If a greater force is required, the user maytwist the primary shaft in one direction more than in the otherdirection to increase the stiffness of the wire, thereby increasing theforce that can be applied to the CTO by the distal tip.

In FIG. 20B, the secondary shaft 2006 is moderately twisted around theprimary shaft 2008 to form a configuration with moderate stiffness. TheCTO wire is kept in moderate configuration by rotating the primary shaft2008 more in one direction than the other direction. The user can rotateclockwise and counter-clockwise as many times as desired as long asthere is a surplus of rotations in one of the directions to maintain amoderate or higher stiffness. The user can continuously rotate theprimary shaft 2008 until the desired target goal of the wire tipcrossing force is achieved.

In FIG. 20C, the secondary shaft 2010 is tightly twisted around theprimary shaft 2012 to form a configuration with high stiffness. The CTOcrossing wire configuration is kept stiff by increasing the rotations infavor of one direction over the other. If the primary shaft 2012 isinitially twisted in the clockwise direction, additional clockwiserotations will increase the stiffness, while counter-clockwise rotationswill decrease the stiffness. Additional clockwise rotation of theprimary shaft 2012 leads to an incremental increase in the amount offorce that the distal tip 2014 of the wire is able to exert on a lesion.Continuous clockwise rotation leads to a tight bond between the primaryshaft 2012 and the secondary shaft 2010, providing additional supportfor the distal tip 2014. Once the primary shaft 2012 is sufficientlytwisted such that the wire has the stiff configuration, the user mayrotate the primary shaft 2012 clockwise and counter-clockwise. The usermay maintain the stiff configuration during these rotations as long asthe counter-clockwise rotations do not exceed the clockwise rotations.The increased stiffness is not permanent. It can be reversed, or theforce applied by the distil tip 2014 on the lesion can be changed, byrotating the primary shaft 2012 counter-clockwise.

The distal tip 2014 can have a shape that is influenced by the twistingof the primary shaft 2012 and secondary shaft 2010. Rotating the primaryshaft 2012 to obtain a stiff configuration may also narrow the loop andreduce the angle formed by the two sides of the loop. Rotating theprimary shaft 2012 in the opposite direction will cause the loop tobecome broader, increasing the angle between the two sides of the loop.The loop can thus have any configuration desired by the user.

The secondary shaft 2010 may have different configurations, such as afree tip, or a welded or connected tip. FIG. 21A shows a wire having aprimary shaft 2100 and a secondary shaft 2102, where the proximal tip2104 of the secondary shaft 2012 is free, i.e., not welded to theprimary shaft 2100. FIG. 21B shows a wire having a primary shaft 2106and a secondary shaft 2108, where the proximal tip 2110 of the secondaryshaft 2008 is welded or connected to the primary shaft 2106. Thesecondary shaft 2108 in the welded configuration may be twisted aroundthe primary shaft 2106 prior to welding, or may be substantiallyparallel to the primary shaft 2106 when the proximal tip 2110 is weldedto the primary shaft 2106. Both free and welded tips can have a similarsecondary shaft configuration.

The configuration is not affected by the length of the secondary shaft,which can have a variety of lengths. The length 2112 of the secondaryshaft 2108 is indicated in FIG. 21B. The length of the secondary shaft2108 can be configured based on the required stiffness of the wire. Thelength of the secondary shaft 2108 can therefore vary from just a loopedtip to extending the entire length of the primary shaft 2106. The wirecan have a pre-formed loop at the distal tip, and the secondary shaft2108 may or may not be twisted around the primary shaft 2110 while theCTO crossing wire is in a relaxed state, i.e., before the user has begunto rotate the primary shaft 2106. The variations in the wire provide thevariations in the force and support needed to cross a lesion in thecoronaries or peripheral arteries and veins.

FIGS. 7A-7D show various configurations of a crossing wire. FIGS. 7A-7Ddemonstrate how the characteristics of the crossing wire can be varied,depending on the desired application. For example, crossing wire 700 inFIG. 7A has a narrower loop 702 than the loop 706 of the crossing wire704 in FIG. 7B. The secondary shaft 708 of wire 700 is shorter than thesecondary shaft 710 of the crossing wire 704. A longer secondary shaftcan provide more support to the main shaft, enabling a higher force tobe applied on a lesion by the loop without the wire bending or buckling.The crossing wire can be configured to bend at a particular point, whichcan influence the width of the loop. For example, crossing wire 712 inFIG. 7C can be configured to bend at one of a variety of points 714-722.Positioning the bending point farther from the leading portion 724 ofthe loop can result in a wider, longer loop, while positioning thebending point closer to the leading portion of the loop can result in anarrower, shorter loop. The position of the bending point can bedetermined by the structure of the wire, for example, by havingdifferent thicknesses along the length of the wire or by having parts ofthe wire made from different materials to make some portions of the wiremore flexible than others. In one aspect of the invention, the distancefrom the leading portion 724 of the loop to the first node 734 isbetween about 1 mm and about 40 mm. In one aspect of the invention, thedistance from the leading portion 738 of the loop to the distal end ofthe catheter is between about 3 mm and about 40 mm.

As shown in FIG. 7A, the wire in some configurations can have a firstloop portion 736 that increases in width from the leading distal end 738to a maximum width 740. The wire includes a second loop portion 742 thedecreases in width from the maximum width 740 to a first node 744. Thewire includes a tail portion 746 distal to the first node 744. Theprimary shaft 700 and secondary shaft 708 may form additional nodes inthe tail portion 746.

The crossing wire can have varying stiffness along its length. Aparticular stiffness is chosen based on the application. The crossingwire can include markers that indicate the proper position of the wirefor a particular stiffness. Occlusions providing mild resistance can becrossed with a less stiff portion of the wire, while severe occlusionscan be crossed with the stiffest portion of the wire. According to oneconfiguration, the crossing wire has three different stiffness valuesalong its length.

The crossing wire 726 in FIG. 7D has a wider loop 728 with a more bluntleading portion 730 than the crossing wires illustrated in FIGS. 7A-7C.The crossing wires illustrated in FIGS. 7A-7D are provided to highlightvarious characteristics of the crossing wire that can be altered ormanipulated to create different configurations of the crossing wire.Some characteristics of the crossing wires shown in FIGS. 7A-7D may beinterchanged and/or combined, and the aspects of the invention are in noway limited to the configurations shown in FIGS. 7A-7D.

FIG. 18 shows a crossing wire in a twisted configuration. The crossingwire has a shape similar to that of a sperm, with a head 1800 and a tail1802. The primary shaft 1804 is bent at the base 1806 of the head 1800,and the first head portion 1808 forms an angle α with respect to theaxis 1810 of the primary shaft 1804. The first head portion 1808 may besubstantially straight until the first transition point 1812. The wirethen bends back toward the axis 1810, forming second head portion 1814.Second head portion 1814 may be substantially straight, or may graduallybend. The second head portion 1814 transitions to a third head portion1816 at a leading distal end 1818 of the wire. The second head portion1814 and third head portion 1816 may form a rounded leading distal end,a pointed leading distal end, or any other leading distal endconfiguration. The third head portion 1816 extends from the leadingdistal end 1818 back toward the proximal end of the wire. The third headportion extends to the second transition point 1820. The firsttransition point 1812 and the second transition point 1820 may be thelocations where the wire forming the head 1800 is farthest from the axis1810 of the primary shaft 1804. After the second transition point 1820,the wire has a fourth head portion 1822 that extends back toward thebase 1806 of the head 1800. The fourth head portion 1822 may form anangle β with respect to the axis 1810 of the primary shaft 1804. Thewire then has a secondary shaft 1824 that wraps around the primary shaft1804. The secondary shaft 1824 wrapped around the primary shaft 1804forms the tail portion 1802. According to one configuration, the firsthead portion 1808 and fourth head portion 1822 are substantiallysymmetrical. According to one configuration, a and 13 are substantiallyequal. In one aspect of the invention, the first head portion 1808 andfourth head portion 1822 form a V-shape (sideways in FIG. 18).

FIG. 19A shows a crossing wire before it has been bent and cured orpreformed into a looped configuration. In one embodiment, the wire hastwo portions, a first portion 1900 and a second portion 1902, and thetwo portions do not have the same stiffness. In one configuration, thefirst portion 1900 is less stiff and more flexible than the secondportion 1902. The first portion 1900 can be bent and cured to form theleading distal end of the wire. The first portion 1900 may form aflexible portion of the wire, and can be radiopaque for bettervisualization under fluoroscopy. The length of first portion 1900 may bebetween 1 mm and 100 mm. The stiffness of the first portion 1900 may beconstant throughout the first portion 1900, or may gradually increasefrom the tip 1904 of the first portion 1900 to the junction 1906 withthe second portion 1902.

The second portion 1902 forms the primary shaft of the crossing wire.The second portion 1902 may also form a portion of the loop when thecrossing wire is bent into a looped configuration. The second portion1902 of the CTO wire may not be radiopaque, and may be stiffer than thefirst portion 1900. The second portion 1902 can allow the first portion1900 to loop around the second portion 1902 with added stability andpush ability due to the double wire support.

FIG. 19B shows a crossing wire in a twisted configuration. The primaryshaft 1908 and first head portion 1910 are formed from the secondportion 1902 in FIG. 19A, while the remaining head portions 1912-1916and the secondary shaft 1918 are formed from the first portion 1900 inFIG. 19A. The wire may transition from the stiffer second portion 1902to the more flexible first portion 1900 at the transition point 1918.Alternatively, the wire may transition from the stiffer second portion1902 to the more flexible first portion 1900 at other positions in theloop 1920.

The second head portion 1912 and third head portion 1914 form theleading distal end 1922 of the crossing wire, and can form a variety ofangles and have a variety of configurations. The leading distal end 1922can have the flexibility to conform to a CTO cap. The wire forming theleading distal end 1922 can also have micro-skives in it to help weakenthe CTO cap without impacting the vessel wall.

The secondary shaft 1918 can wrap around the primary shaft 1908, forminga tail that adds propulsion value and stiffness to the leading distalend 1922 of the crossing wire. As the tail becomes more tightly wrappedaround the primary shaft 1908, for example, by twisting the primaryshaft 1908, the gram weight on the CTO wire and/or crossing deviceincreases along with its ability to penetrate resistant material such asa CTO cap. The primary shaft 1908 can have any diameter deemed fit for aparticular CTO crossing. In one aspect, the diameter of the primaryshaft 1908 is between 0.09″ and 0.40″. In one aspect, the diameter ofthe primary shaft 1908 is one or more of 0.09″, 0.14″, 0.18″, 0.21″,0.24″, 0.27″, 0.28″, 0.30″, 0.33″, 0.35″, and 0.40″. The loop may havethe same diameter as the primary shaft, or a greater or lesser diameter.

The primary shaft and secondary shaft may have the same diameter alongtheir entire length. Alternatively, the primary shaft may have a firstdiameter along a proximal portion of the shaft, and a second diameter atthe distal portion of the shaft. FIG. 22 shows an example configurationin which the primary shaft 2200 has proximal portion 2202 having a firstdiameter, for example, 0.35″. The primary shaft 2200 has a distalportion 2204 having a second diameter, for example, 0.175″. Thesecondary shaft 2206 may also have the second diameter, for example,0.175″. The combined width 2208 of the loop formed by the distal portion2204 of the primary shaft 2200 and the secondary shaft 2206 may equalthe diameter of the proximal portion 2202 of the primary shaft 2200, forexample, 0.35″. The diameter values provided herein are solely examples,and the embodiments of the invention are not limited to these values.

The secondary shaft 2206 may be bonded to the distal portion 2204 of theprimary shaft 2200. For example, the secondary shaft may be bonded tothe primary shaft at the proximal end 2210 of the secondary shaft 2206.The secondary shaft 2206 may be bonded to the distal portion 2204 of theprimary shaft 2200 at a plurality of other locations. Alternatively, thesecondary shaft 2206 may not be bonded to the distal portion 2204 of theprimary shaft 2200. The examples below may also have one or more pointsat which the secondary shaft is bonded to the primary shaft, or thesecondary shaft and primary shaft may not be bonded.

FIG. 23 shows a configuration in which the diameter of the primary shaft2300 is constant along the length of the primary shaft 2300, and isequal to the diameter of the secondary shaft 2302. For example, theprimary shaft and the secondary shaft may each have a diameter of 0.35″,while the width 2304 of the loop formed by the primary shaft 2300 andsecondary shaft 2302 is twice the diameter of each shaft, for example,0.70″.

FIG. 24 shows an example configuration in which the primary shaft 2400has a proximal portion 2402 having a first diameter, for example, 0.18″.The primary shaft 2400 has a distal portion 2404 having a seconddiameter, for example, 0.09″. The secondary shaft 2406 may also have thesecond diameter, for example, 0.09″. The combined width 2408 of the loopformed by the distal portion 2404 of the primary shaft 2400 and thesecondary shaft 2406 may equal the diameter of the proximal portion 2402of the primary shaft 2400, for example, 0.18″.

FIG. 25 shows a configuration in which the primary shaft 2500 and thesecondary shaft 2502 each have the same diameter, for example, 0.18″,while the width 2504 of the loop formed by the primary shaft 2500 andsecondary shaft 2502 is twice the diameter of each shaft, for example,0.36″. A user may stiffen the wire by rotating the primary shaft 2500clockwise, for example, and loosen the wire by performing acounter-clockwise rotation, for example, of the primary shaft 2500.

FIG. 26 shows an example configuration in which the primary shaft 2600has proximal portion 2602 having a moderately stiff body and a firstdiameter, for example, 0.14″. The primary shaft 2600 has a distalportion 2604 having a second diameter, for example, 0.07″. The secondaryshaft 2606 may also have the second diameter, for example, 0.07″. Thecombined width 2608 of the loop formed by the distal portion 2604 of theprimary shaft 2600 and the secondary shaft 2606 may equal the diameterof the proximal portion 2602 of the primary shaft 2600, for example,0.14″.

FIG. 27 shows a configuration in which the primary shaft 2700 and thesecondary shaft 2702 may each have a diameter of 0.14″, while the width2704 of the loop formed by the primary shaft 2700 and secondary shaft2702 is twice the diameter of each shaft, for example, 0.28″. The 0.28″loop may be stiffened by tightening the helical distal portion of theprimary shaft 2700 and/or the helical secondary shaft 2702 by rotatingthe primary shaft 2700 clockwise, for example. The stiffness of the0.28″ loop may be reduced by rotating the primary shaft 2700 in theopposite direction, for example, counter-clockwise. The loop in theconfiguration of FIG. 27 may be stiffer than the loop in theconfiguration of FIG. 24, because the primary and secondary helicalwires forming the loop are thicker relative to the diameter of theproximal portion of the primary shaft than in FIG. 24.

As described above, the primary shaft and the secondary shaft of thewire may or may not be bonded to one another. FIG. 28A shows aconfiguration in which the primary shaft 2800 is a straight shaft, andthe secondary shaft 2802 is a helical shaft that winds around thestraight shaft 2800. The proximal end 2804 of the helical secondaryshaft 2802 may be independent of, i.e. not bonded to, the primary shaft2800. FIG. 28B shows a configuration in which the primary shaft 2806 isstraight shaft, and the secondary shaft 2808 is a helical shaft. Theproximal end 2810 of the helical secondary shaft 2808 is bonded to theprimary shaft 2806. The secondary shaft 2808 may be additionally oralternatively bonded to the primary shaft at other points, for example,on or more of the crossing points 2812, 2814, 2816 shown in FIG. 28B.Bonding the primary shaft 2806 to the secondary shaft 2808 increases thestiffness of the wire and the loop 2818 at the distal end of the wire.The helical secondary shaft 2808 may be integrally formed with theprimary shaft 2806, or may be separately formed and then bonded to theprimary shaft to form a continuous wire, for example, at or near theloop 2818. The helical secondary shaft 2808 may have the same diameteras the primary shaft 2806, or a different diameter. The primary shaft2806 may also have varying diameters along its length.

FIG. 29 shows a configuration in which both the distal portion 2902 ofthe primary shaft 2900 and the secondary shaft 2904 have a helicalconfiguration. The secondary shaft 2904 can be bonded to the primaryshaft 2900 at the proximal end 2906 of the secondary shaft 2904, and atother points, for example, points 2908, 2910 along the length of thesecondary shaft. The distal tip 2912 may have a shape that can beadjusted by the user, for example by twisting the primary shaft 2900clockwise or counter-clockwise. The proximal portion of the primaryshaft 2900 may be integrally formed with the distal portion 2902 of theprimary shaft 2900 and the secondary shaft 2904. Alternatively, thedistal portion 2902 of the primary shaft 2900 and the secondary shaft2904 may be integrally formed, and may be bonded to the proximal portionof the primary shaft 2900 to form a continuous wire. This configurationmay be useful when the proximal portion of the primary shaft 2900 has adifferent diameter than the distal portion 2902 of the primary shaft2900 and the secondary shaft 2904. The wire may be preformed to have thetwisted shape shown in FIGS. 22-29, or the twisted shape may be obtainedin situ, for example, by rotating the primary shaft.

According to some aspects of the invention, the wire can be adapted foruse in all arteries and veins. The gram tip stiffness of the wire canstart at 1-3 grams. The wire can be made from a hydrophilic ornon-hydrophilic material, and the choice of the material may be based onthe lesion. The crossing wire can be encased in an outer shell. Theouter shell can prevent the proximal end of the secondary shaft frominadvertently catching on tissue. The outer shell may be useful whennavigating the crossing wire through particular veins and arteries, forexample, the aortic junction.

FIG. 30A shows a crossing wire 3000 encased in an outer shell 3002. Theouter shell may be designed to have 1:1 torque and 1:1 pushability andtracability. The proximal two-thirds of the crossing wire 3000 can bestiff. The distal third of the wire 3000 has a pre-shaped loop. Thestiffness of the distal third can be increased or decreased by rotatingthe primary shaft. For example, if the primary shaft is initiallyrotated clockwise, additional clockwise rotations will increase thestiffness of the distal end, while counter-clockwise rotations willdecrease the stiffness of the distal end. The stiffness and force bygram is transmitted to the outer shell 3002, making the combination ofthe crossing wire 3000 and outer shell 3002 equally stiff. The stiffnesscan be reduced by counter-clockwise rotation, for example, reducing theforce and inner gram weight therefore the entire device including thecrossing wire 3000 and outer shell 3002 can become soft or floppy basedon the number of counter-clockwise rotations. FIG. 30B shows anotherexample of a wire 3004 encased in an outer shell 3006. FIG. 30C shows acrossing wire 3008 that is not encased in an outer shell.

There is a direct force communication between the crossing wire and theouter shell. The wire, either encase in an outer shell or not encased,can have a configuration that is pre-set before the wire is introducedinto the body. The wire can have an angled or straight configuration.Each configuration can have a similar force transmission without losingthe pre-shaped configuration.

The crossing wire encased in the outer shell can have different sizes,for example, the combined device may have a cross-section between0.09″-0.35″. For example, the cross-section may be 0.09″, 0.14″, 0.21″,0.28″, or 0.35″. The variety in sizes allows for the wires toaccommodate a wide range of veinal size spectrums.

FIGS. 31A-31C show crossing wires according to some aspects of theinvention. FIG. 31A shows the length “L” of the secondary shaft 3101.The length L of the secondary shaft 3101 can vary depending on the sizeand type of the crossing wire. Further, as the distal tip of the wire isused to interrogate a lesion, the primary shaft 3100 may be pushedtoward the lesion, causing the length L of the secondary shaft 3101 tobecome longer. The primary shaft 3100 may have varying stiffness alongits length. For example, the portion of the wire that initially formsthe loop may have a first stiffness. As the primary shaft 3100 is pushedtoward the lesion, the secondary shaft 3101 may become longer, and theloop may be formed from a portion of the primary shaft 3100 having agreater stiffness than the original stiffness of the loop.

FIG. 31B shows a crossing wire wherein the secondary shaft 3102 is notbonded to the primary shaft 3104. FIG. 31C shows a crossing wire whereinthe proximal end 3106 of the secondary shaft 3108 is bonded to theprimary shaft 3110.

FIGS. 32A-32C show some aspects of the outer shell. As shown in FIGS.32A and 32B, the distal end of the outer shell may be open (FIG. 32A) orclosed (FIG. 32B). In the configuration of FIG. 32A, the outer shellkeeps the loop at the distal end of the crossing wire narrow andprovides support. The outer shell functions as the primary leading wiredespite the amount of force generated from the loop. The crossing wirecan be modulated to have variable degrees of stiffness, and can be usedfrom within the outer shell. Alternatively, as shown in FIG. 32C, thedistal end of the crossing wire 3200 can exit distal end of the outershell 3202, and can work independently of the outer shell 3202. Thedistal end of the crossing wire 3200 can advance past the distal end ofthe outer shell 3202, and can become the leading wire, as shown in FIG.32C.

FIG. 32B shows the outer shell having a closed distal end. The action ofthe crossing wire is translated and transmitted by the outer shell tothe obstruction or lesion in the patient's body. The stiffness of thecrossing wire inside the outer shell can be varied from floppy to verystiff by rotating the primary shaft of the crossing wire.

The force generation and stiffness of the crossing wire can be based ona mechanical configuration change, and hence the stiffness can bevariable. However, the wire can also have a configuration in which thedistal end of the wire applies a specific force that is constant. Forexample, the crossing wire can be formed to have a closed loop, meaningthat the primary and secondary shafts are bonded or welded such that theloop has a predetermined stiffness.

For example, FIGS. 33A-33D demonstrate how the stiffness of the loopsmay be varied by varying the configuration of the crossing wire. In FIG.33A, the secondary shaft 3300 is loosely wrapped around or entwined withthe primary shaft 3302, resulting in a relatively floppy wire. Thesecondary shaft 3300 and primary shaft 3302 may be disposed in an outershell 3304. In FIG. 33B, the secondary shaft 3306 is more tightlywrapped around or entwined with the primary shaft 3308, resulting in awire with mild stiffness. The secondary shaft 3306 and primary shaft3308 may be disposed in an outer shell 3310. In FIG. 33C, the secondaryshaft 3312 is even more tightly wrapped around or entwined with theprimary shaft 3314, resulting in a wire with moderate stiffness. Thesecondary shaft 3312 and primary shaft 3314 may be disposed in an outershell 3316. In FIG. 33D, the secondary shaft 3318 is very tightlywrapped around or entwined with the primary shaft 3320, resulting in awire with maximum stiffness. The secondary shaft 3318 and primary shaft3320 may be disposed in an outer shell 3322.

In some aspects, the crossing wire has a spring-like configuration. FIG.34A shows a wire 3400 having a spring-like configuration. The secondaryshaft may circumscribe the primary shaft such that there is spacebetween the primary shaft and the secondary shaft. The length “Li” ofthe helical portion in FIG. 34A may be about 60 mm, for example. FIG.34B shows another crossing wire 3402 having a spring-like configuration.The length “Li” of the helical portion in FIG. 34B may be about 60 mm-80mm, for example. The width “W” of the crossing wire proximal to the loop3404 is wider for the crossing wire 3402 than for a wire having thesecondary shaft wound tightly around the primary shaft, such as thecrossing wire shown in FIG. 33D, for example. Another crossing wirehaving a spring-like configuration is shown in FIG. 34C. The secondaryshaft 3406 can be helically wrapped around the primary shaft 3408without contacting the primary shaft 3408, except at the distal end 3410of the secondary shaft 3406. The secondary shaft 3406 in thisconfiguration can prevent buckling of the crossing wire, and can act asa support system that transmits energy from the distal tip of thecrossing wire to the lesion to be crossed. In one aspect, the secondaryshaft 3406 can be circumferentially wound around the primary shaft 3408to create the spring-like support feature.

The helical portion of the wire can be formed from a single wire ormultiple wires. For example, FIG. 35A shows a side view of a crossingwire having a helical portion formed from two wires 3500, 3502. FIG. 35Bshows a top-down view of the wire of FIG. 35A. The crossing wires inFIGS. 34A-C, 35A, and 35B may be considered to have a “circumferential”configuration.

FIG. 36 shows a crossing wire having a primary shaft 3600 and twosecondary shafts 3602, 3604. The two secondary shafts 3602, 3604 areconnected to the distal tip 3606 of the primary shaft 3600. The primaryshaft 3600 and two secondary shafts 3602, 3604 form a loop at the distalend of the crossing wire. The two secondary shafts 3602, 3604 can bewound around the primary shaft 3600. The crossing wire in FIG. 36 may beconsidered to have a “longitudinal” configuration. In thisconfiguration, the secondary wire spans a greater longitudinal distance,i.e., distance along the length of the primary shaft, per revolutionaround the primary shaft than in the circumferential configuration. Thesecondary shaft in the longitudinal configuration may also be closer tothe primary shaft in the longitudinal configuration. The distancebetween the primary shaft and the secondary shaft is discuss in moredetail with respect to FIG. 37. The crossing wire can include additionalwires, for example, more than two primary or secondary shafts. Thenumber of wires will determine the stiffness of the distal end of thecrossing wire, with more wire resulting in increased stiffness.

In one aspect of the invention, varying the distance between the primaryshaft and the secondary shaft can result in a variation in the stiffnessof the distal end of the shaft. FIG. 37A shows a crossing wire having aprimary shaft 3700 and a secondary shaft 3702. FIG. 37B shows anenlarged view of the region enclosed by the dashed circle in FIG. 37A.The distance “D” between the primary shaft 3700 and the secondary shaft3702 can be increased or decreased to decrease or increase the stiffnessof the crossing wire. FIG. 37C shows another configuration of a crossingwire having a gap 3704 between the primary shaft 3706 and the secondaryshaft 3708.

FIGS. 38A and 38B show crossing wires having a dual longitudinal helicalwire configuration. In one aspect, the primary and secondary shafts bothhave a helical shape.

FIGS. 39A-39D show a crossing wire according to one aspect of theinvention. FIG. 39A shows a crossing wire configured to pass through alumen of a catheter. The crossing wire includes a loop 3900 at a distalend of the crossing wire. The loop 3900 has a configuration thatprevents a width LW of the loop 3900 from exceeding a width of a tissuelumen in which the crossing wire is disposed. The loop 3900 has a pairof lateral opposing portions 3904, 3906 configured for alignment with awall of the tissue lumen and a leading portion 3908 interconnecting thepair of lateral opposing portions 3904, 3906. The leading portion 3908is configured to interrogate a lesion in the tissue lumen. The loop 3900has a length LL in an axial direction of the crossing wire extendingfrom the leading portion 3908 to proximal ends of the pair of lateralopposing portions 3904, 3906, and the length LL is perpendicular to thewidth LW. The length LL of the loop 3900 is at least twice the width LWof the loop 3900.

In one aspect, the length LL of the loop 3900 is three, four, or fivetimes the width LW of the loop 3900. In one aspect, the length LL of theloop 3900 is more than five times the width LW of the loop 3900.

As shown in FIG. 39A, the crossing wire may also have a shaft 3902 thatis formed from the primary shaft 3904 and secondary shaft 3906, whichare intertwined. The pair of lateral opposing portions 3904, 3906 andthe leading portion 3908 can have a circular cross section at the loop3900. Alternatively, as shown in FIG. 39D, the pair of lateral opposingportions 3904, 3906 and the leading portion 3908 can have a rectangularcross section at the loop 3900. For example, a wire having a circularcross-section can be ground or shaved to have a rectangularcross-section, or the crossing wire can be formed from a wire that ismanufactured to have a non-circular cross-section. FIG. 39B shows anenlarged image of the shaft 3902. It is evident from FIG. 39B that theshaft is formed from two wires, the primary shaft and the secondaryshaft. The primary shaft and the secondary shaft are preciselyintertwined along the length of the shaft 3902. FIG. 39C shows anenlarged image of the loop 3900.

FIG. 39D shows a crossing wire with a rectangular cross-section. Thecrossing wire in the loop 3900 is not twisted, while the crossing wirein the shaft 3902 is twisted. One of the pair of lateral opposingportions 3904, 3906 of the loop 3900 is directly connected to theprimary shaft, and the other of the pair of lateral opposing portions3904, 3906 is directly connected to a secondary shaft of the crossingwire. The secondary shaft is configured to wrap around the primaryshaft. The leading portion 3908 of the loop 3900 can be flat, due to therectangular cross-section of the wire. The flat, wide surface of thewire is perpendicular to the plane of the loop, and faces outward fromthe center of the loop. Thus, the flat, wide surface of the pair oflateral opposing portions 3904, 3906 contacts the tissue over a largersurface area than if the crossing wire in the loop 3900 were twisted.The large surface area can distribute forces so that the crossing wireis less likely to slice or puncture the wall of the tissue. The flat,wide surface of the pair of lateral opposing portions 3904, 3906 alignswith the wall of the tissue lumen, and can be flush against the wall ofthe tissue lumen.

FIG. 39E shows a cross-section of the crossing wire in the loop 3900.The cross-section is rectangular, with two short edges 3910, 3912, andtwo long edges 3914, 3916. The outer-facing side of the crossing wire,which corresponds to the long edge 3914 in FIG. 39E, contacts the wallof the tissue, spreading the forces applied to the wall of the tissueover the wide surface of the crossing wire. In one aspect, the pair oflateral opposing portions 3904, 3906 and the leading portion 3908 of theloop 3900 form a plane, and the two long edges 3914, 3916 areperpendicular to the plane of the loop.

FIGS. 40-42 show crossing wires according to some additional aspects ofthe invention. Each of the crossing wires in FIGS. 40-42 has a primaryshaft and a secondary shaft that are flat, i.e., have a rectangularcross-section, at the loop and along the shaft of the crossing wire. InFIGS. 40-42, the crossing wire is twisted two or more times in the loopportion. However, the twists are located proximal to the widest sectionof the loop. The wide, flat side of the crossing wire in each of theloops is perpendicular to the plane of the loop at the widest section ofthe loop. The wide, flat side of the crossing wire provides a stablesurface that can be aligned with the wall of the tissue. The wire in theshaft is twisted more tightly than the wire in the loop. While the wirein the loop may be twisted one, two, or three times in each of the pairof lateral opposing portions of the loop, the primary and secondaryshafts are much more tightly twisted in the shaft, for example, five,ten, or twenty times in the equivalent distance. The length LL of theloop with respect to the width LW may be shorter, as in FIG. 40, orlonger as in FIG. 42.

FIGS. 43A-43D shows crossing wire shafts according to some additionalaspects of the invention. The shaft can have a variety of width. Theterm “width” can refer here to the longest dimension of thecross-section of the shaft. FIGS. 44A, 44B, 45A, and 45B show crossingwire loops according to some additional aspect of the invention. Thelooped portion of the crossing wire can have a rectangularcross-section. As shown in FIG. 45A, the secondary shaft 4500 may bewelded to the primary shaft 4502 without being twisted around theprimary shaft 4502. The crossing wires can have variable weights,widths, and stiffnesses of the looped portion and shaft. The length ofthe loop from the distal tip to the point where the primary shaft meetsthe secondary shaft may be varied. For example, the crossing wires inFIGS. 44A and 44B have longer loops than the crossing wires in FIGS. 45Aand 45B. In some embodiments, the loop has a weight between 3 grams and30 grams.

FIG. 46 demonstrates a process for creating a wire having a non-circularcross-section in the loop portion from a wire having a circularcross-section. In FIG. 46, the hashed portion 4600 of the crossing wire4602 can be shaved off, resulting in the crossing wire 4604. Thenarrowed portion 4606 of the crossing wire 4604 can be used to form theloop of the crossing wire, by connecting the opposite ends 4608, 4610.

FIGS. 47A-47D show additional aspects of formation of a crossing wirehaving a non-circular cross-section. FIG. 47A shows how the crossingwire can be shaved along a first side 4700 and a second side 4702 tocreate first and second flat edges and first and second round edge. Thewire can be used in this formation to cross occlusions. Alternatively,the round portions 4704, 4706 can be shaved, resulting in a wire havinga square or rectangular cross-section, as shown in FIG. 47B. In oneaspect, the shaving is performed on the portion of the wire that is usedto create the loop. FIGS. 47C and 47D further demonstrate how thecrossing wire can be shaved to reduce its diameter or cross-section.

FIGS. 48A-48C show crossing wires according to some aspects. As shown inFIG. 48A, the crossing wire may have a shaved cross-section at thedistal portion 4800 of the loop 4802. As shown in FIG. 48B, the crossingwire may have a shaved cross-section throughout the loop 4804. As shownin FIG. 48C, the crossing wire may have a loop 4806 that is not shaved.The primary shaft and secondary shaft of the crossing wires may bewelded or may not be welded to each other.

As an alternative to shaving, a non-circular cross-section of the wiremay be achieved by combining multiple wires together. For example, FIG.48D shows a distal end of a crossing wire that is formed from foursub-wires 4808-4814. The four sub-wires 4808-4814 can be aligned to forma flat surface. The sub-wires can be welded or adhered together to formthe crossing wire, and more or fewer than four sub-wires can be used.The individual sub-wires may have circular or non-circularcross-sections.

In one aspect of the invention, the wire may have abrasive elements atthe distal tip of the wire. For example, FIG. 49A shows a crossing wirein a loosely wound formation with abrasive elements 4900 on the loop4902. FIG. 49B shows a crossing wire in a more tightly wound formationwith abrasive elements 4904 on the loop 4906. The abrasive elements maybe adhered to the wire, or the wire may be roughened to create theabrasive elements. The abrasive elements can interrogate a lesion, andcan aid a physician in eroding away at and crossing a lesion.

FIGS. 50A and 50B show crossing wires having a welded loop according tosome aspects. In FIG. 50, the loop 5000 can be welded to the shaft 5002.Alternatively, one side of the loop may be formed by the primary shaft,while the other side is formed by the secondary shaft. The proximal endof the secondary shaft may be welded to the primary shaft, for example,at the point 5004 on FIG. 50B.

FIG. 51 shows a crossing wire according to one aspect. The width 5100 ofthe loop 5102 can be between 1 mm-14 mm. The primary shaft 5104 andsecondary shaft 5106 may individually or in combination have a diameterof 0.09″ to 0.35″, for example.

In some aspects, the crossing wire is used in conjunction with acatheter. FIG. 8A shows a catheter with a side opening and a crossingwire configured in one aspect of the invention. The catheter 800includes a hole 802 in a side surface of the catheter 800. As shown inFIG. 8A, the main shaft 804 of the crossing wire is disposed in thelumen of the catheter 800, while the secondary shaft 806 is at leastpartially disposed outside the lumen. In FIGS. 8B and 8D, a portion 808of the secondary shaft 806 enters the lumen through the hole 802. InFIGS. 8A and 8C, the secondary shaft 806 wraps around the outside of thecatheter 804 without entering the hole 802. The catheter according toone aspect can be prepared with secondary shaft 806 the crossing wire atleast partially disposed outside the lumen before the catheter isintroduced into the vessel or artery. As show in FIGS. 8A-8D, the loopcan have various configurations. For example, the loop can be pointed,rounded, or peaked, as in the loop 810. As would be understood by one ofordinary skill in the art from the configuration of the catheter 800 andcrossing wire 806 in FIGS. 8B and 8D, the catheter according to someconfigurations can be formed without a hole 802, and the secondary shaft806 can remain outside of the catheter along its length.

FIG. 8E shows a catheter and crossing wire having another configuration.The main shaft 814 of the crossing wire is disposed within the lumen ofthe catheter 812, while the secondary shaft 818 is disposed outside thelumen. The crossing wire includes an inverted loop 816.

FIGS. 9A-9C shows additional configurations of looped crossing wiresaccording to some aspects of the invention. As shown in FIGS. 9A-9C, theintertwined shafts of the wire may have a variety of shapes, as may theloops.

FIG. 10 shows a device 1000 configured in one aspect of the invention,in which two additional inner catheters 1002, 1004 are disposed withinthe outer catheter 1002. The inner catheters can be stationary, mobile,or a combination of both. The device 1000 in FIG. 10 has one innercatheter 1004 that is stationary, and one inner catheter 1006 that ismobile. The mobile inner catheter 1006 can be moved longitudinally alongthe length of the outer catheter 1002, and can even be pushed to extendbeyond the distal end 1008 of the outer catheter 1002, as shown in FIG.10. The mobile inner catheter 1006 can also be manipulated radiallyaround the inside of the outer catheter 1002. As shown in FIG. 10, thecrossing wire 1010 passes through the stationary inner catheter 1004 andthe mobile inner catheter 1006, and forms a loop, or U-turn, at thedistal end of the device 1000. The leading portion 1012 of the loop isbrought into contact with the lesion. FIG. 10 also shows a torque device1014 that can be used to grasp the two wires to prevent them from movingwith respect to one another. A physician can use the torque device 1014to manipulate the crossing wire and loop. For example, once the outercatheter has neared the lesion, the loop can be extended beyond thedistal end of the catheter to contact the lesion, and then the physiciancan twist the torque device 1014 to create one or more figure eight-likesegments in the distal portion of the wire. The physician can also twistone shaft of the crossing wire 1010 to create a twisted loop at thedistal end of the crossing wire 1010. For example, the physician maytwist, or rotate, the shaft disposed in the mobile inner catheter 1006,creating a twisted loop distal to the distal end of the mobile innercatheter 1006 and the stationary inner catheter 1004. Alternatively, thephysician may twist the shaft disposed in the stationary inner catheter1004 to create the twisted loop.

According to one aspect, a method for crossing a lesion involves movingthe portion of the crossing wire 1010 in the mobile inner catheter 1006with respect to the portion of the crossing wire 1010 in the stationaryinner wire 1004. This causes the leading portion 1012 of the loop toundergo a fan-like motion. One side of the loop portion is stationary,while the other side moves in an arc around it. The leading portion 1012of the loop acts like a sweeping blade that shaves into the lesion.

FIG. 11A shows another configuration of a device with two innercatheters disposed within the outer catheter. An additional innercatheter can be provided for a conventional and/or additional guidewire.The additional inner catheter 1100 is shown in FIGS. 11B and 11C. Theadditional inner catheter may be mobile, or may be fixed to the outercatheter or one or both of the inner catheters. The inner supportcatheters support the looped CTO wire and help manage the portions ofthe wire. The inner support catheters also provide column strength toprevent buckling of the wire. The inner support catheters may have alength that is longer than the length of the outer catheter, so that thephysician can push the proximal end of one of the inner supportcatheters, causing the distal end to extend beyond the distal end of theouter catheter.

FIG. 12 shows a configuration of a device wherein at least one innercatheter 1200 is mobile with respect to the outer catheter. The crossingwire 1202 forms a continuous loop at both the distal end 1204 andproximal end 1206 of the device. The crossing wire 1202 may have avariety of stiffnesses along its length, and the physician may positionthe wire such that the distal end 1204 has a preferred stiffness. Forexample, the physician may initially interrogate the lesion with aregion of the wire having a first stiffness. If the distal end 1204 ofthe wire does not have a sufficient stiffness to cross the lesion, thephysician may pull one side of the crossing wire 1202 such that adifferent portion of the wire forms the distal tip. The physician maypull one side of the crossing wire 1202 until a portion of the wirehaving a greater stiffness than the first stiffness is positioned at thedistal end 1204. The physician can then use the new, stiffer distal end1204 to interrogate the legion. In one aspect, the crossing wire hasthree or more different stiffnesses along its length.

FIG. 13A shows a configuration of a device having a wheel to facilitatetwisting of the crossing wire. The wheel 1300 is disposed within theproximal loop 1302 of the crossing wire. The wheel 1300 can facilitatetwisting of the crossing wire. FIG. 13B shows an enlarged view of thewheel 1300 of FIG. 13A. The wheel 1300 includes an outer circle 1304that represents an outer grabber that helps rotate the wire. Thesemicircles 1306 represent an inner grabber that helps adjust theposition of the leading distal end of the loop. For example, each spacebetween two adjacent semicircles may correspond to a distal end having aparticular stiffness. The physician may interrogate the lesion with thecrossing wire aligned at a position indicated by a first semicircle suchthat the distal end has a first stiffness. If the first stiffness isinsufficient to cross the lesion, the physician may rotate the wheel1300 to a second position indicated by a second semicircle thatcorresponds to a distal end of the wire having a greater stiffness. Thewheel 1300 can aid the physician in adjusting the stiffness of thedistal end of the wire while the crossing wire is in situ.

FIG. 14 shows a configuration of a device in which a plurality ofcatheters are disposed within the outer catheter 1400, and the outercatheter 1400 includes a hole 1402 in a side surface. The crossing wire1404 exits the distal end of the catheter 1400, and then reenters thelumen of the catheter through the side hole 1402.

In some configurations of the device, the crossing wire has across-section that is not circular. FIG. 15A shows a crossing wire 1500having a circular cross-section 1502. However, it may be beneficial tohave a cross-section that is not circular, to allow for a smallersurface area of the wire to interrogate the lesion. The cross-sectionmay have a variety of shapes. For example, FIG. 15B shows a firstrectangular cross-section 1504, and FIG. 15C shows a second rectangularcross-section 1506. FIG. 15D shows an oval cross-section 1508. FIG. 15Eshows a cross-section 1510 with a serrated edge. The serrated edge maybe applied to any cross-section to aid the physician in interrogatingthe lesion. In one aspect, the longest dimension of the cross-section ofthe crossing wire is one or more of 0.09″, 0.14″, 0.18″, 0.21″, 0.24″,0.27″, 0.28″, 0.30″, 0.33″, 0.35″, and 0.40″.

FIG. 16 shows an example of a loop having a rectangular cross-section.The pre-formed CTO wires can be produced from a single material, and thetwo sides of the wire and the looped portion can be integrally formed.Alternatively, the sides of the wire may be made from a first material,and the looped portion made be made of a second material, and the twomaterials may be welded together to form a continuous wire. This enablesthe side portions of the wire to be formed from a material that hasproperties that are different from the material properties of the loopedportion. For example, it may be beneficial to have the looped portionformed from a material that is more resistant to bending than thematerial from which the side portions are formed. As an additionalexample, the sides and looped portion of the wire may all be formed fromthe same material, but may have different properties that change thecompliance of the wire. For example, the wire at looped portion may bethicker or thinner than the wire at the side portions, making the loopedportion more or less resistant to bending than the side portions.

Existing CTO crossing devices are too large to be used in the arteriesbelow the knee. The present device can have a size that allows it to beused below the knee, for example, throughout the vasculature illustratedin FIG. 17. The device can be used in vessels having a diameter between1.5 mm and 30 mm, according to some aspects. According to one aspect,the catheter is a 0.035″ catheter. According to one aspect, the crossingwire is a 0.018″ wire. The embodiments of the invention are not limitedto these dimensions.

The CTO specialty wire can have the same or varying degrees and/orcombinations of rigidity and/or column strength so that the loop at theend can be moved in and out to the desired portion/rigidity/strengthwire for a particular application. The combination(s) of rigidity can bepredetermined.

The embodiments illustrated and discussed in this specification areintended only to teach those skilled in the art how to make and use theinvention. In describing embodiments of the invention, specificterminology is employed for the sake of clarity. However, the inventionis not intended to be limited to the specific terminology so selected.The above-described embodiments of the invention may be modified orvaried, without departing from the invention, as appreciated by thoseskilled in the art in light of the above teachings. Moreover, featuresdescribed in connection with one embodiment of the invention may be usedin conjunction with other embodiments, even if not explicitly statedabove. It is therefore to be understood that, within the scope of theclaims and their equivalents, the invention may be practiced otherwisethan as specifically described.

1-17. (canceled)
 18. A device for crossing a lesion in a tissue lumen,comprising: a catheter; a crossing wire configured to pass through alumen of the catheter, the crossing wire including a loop at a distalend of the crossing wire, the loop having a configuration that preventsa width of the loop from exceeding a width of the tissue lumen, and theloop having a pair of lateral opposing portions configured for alignmentwith a wall of the tissue lumen and a leading portion interconnectingthe pair of lateral opposing portions, the leading portion beingconfigured to interrogate the lesion; and a stationary inner catheterdisposed within the catheter, the stationary inner catheter including asecond lumen therein; wherein an outer surface of the stationary innercatheter is fixed to an inner surface of the catheter.
 19. The devicefor crossing a lesion according to claim 18, further comprising: amobile inner catheter disposed within the lumen of the cathetereccentric to the stationary inner catheter, the mobile inner catheterforming a third lumen therein, the mobile inner catheter configured tomove axially and radially with respect to the stationary inner catheter.20. The device for crossing a lesion according to claim 19, wherein afirst proximal side of the loop is configured to be disposed within thesecond lumen, and wherein a second proximal side of the loop isconfigured to be disposed within the third lumen.
 21. A device forcrossing a lesion in a tissue lumen, comprising: a catheter forming alumen; and a crossing wire configured to pass through the lumen of thecatheter, the crossing wire including a primary shaft and a loop at adistal end of the primary shaft, the loop having a configuration thatprevents a width of the loop from exceeding a width of the tissue lumen,and the loop having a leading portion configured to interrogate thelesion, wherein the crossing wire has a first configuration in whichopposing lateral sides of the loop are not twisted or are twisted by afirst amount, and a second configuration wherein the opposing lateralsides of the loop are twisted by a second amount that is different fromthe first amount, wherein the crossing wire can be changed from thefirst configuration to the second configuration by twisting the primaryshaft at a position proximal to the catheter.
 22. The device accordingto claim 21, wherein a first side of the opposing lateral sides of theloop is directly connected to the primary shaft, wherein a second sideof the opposing lateral sides of the loop is directly connected to asecondary shaft of the crossing wire, and wherein the primary shaft andthe secondary shaft are disposed inside the lumen of the catheter. 23.The device according to claim 21, wherein in the second configuration,the opposing lateral sides of the crossing wire twist about each other aplurality of times.
 24. The device according to claim 21, wherein ashape of the loop at a position distal to the catheter is configured tochange when a rotational force is applied to the primary shaft at aposition proximal to the catheter.
 25. A method for crossing a chronictotal occlusion (CTO), comprising: inserting a catheter having a loopedwire with a rectangular cross-section disposed in a lumen of thecatheter into an occluded vessel; extending a distal end of the loopedwire beyond a distal end of the catheter to contact an occlusion, thelooped wire being positioned such that a long edge of the rectangularcross-section contacts a wall of the occluded vessel; grasping thelooped wire at a position proximal to a proximal end of the catheter;and rotating the grasped looped wire back and forth through an angleless than 360 degrees while maintaining the distal end of the loopedwire in contact with the occlusion to erode the occlusion.
 26. Themethod for crossing a CTO according to claim 25, further comprising:twisting the grasped looped wire through an angle greater than 360degrees while pressing the distal end of the looped wire against theocclusion such that sides of the looped wire become entwined beyond thedistal end of the catheter.